J e hopkins



July 29, 1930; Re. 17,757

APPARATUS AND METHOD FOR REGOVERING PRECIOUS METALS ksheets shsgt '1Original Filed June Jwumlioz APPARATUS AND-METHOD FOR RECOVERINGPRECIOUS METALS 2 Sheets-Sheet 2 ea (5. fl pkina.

J. E}. HOPKINS Original FiladJune 21, 1926 July 29, 1930.

Reissuecl July 29, 1930 JAMES E HQPK TN 0E DENV R, CQLQI AD THE NASQEN'IAMF A QQBRQBATIQN,

SSEGEIQRJ BY A SIQNMENT$s IQ OF DENVER, COLORADO, A oonronn rronABIEABATUS AND METHQD FQIR; RECQVERING PREQ'IQ'US, MEIAL S Mginal No.1,678,142, dated July 24, 1928, Serial No. 1175383., filed June 21,192.6. Applioatiqn to; reissue flIed Jenuary12; 1930. Serial HQ. 419 607his inven ie re a es n imp o men in.

apparatus. and method its o e ng go d and platinum Values fromaur-iterons and plati-niferous materials and end It s Well kn wn o: thoser ed. in his art that gold will quite r dily form a mailge s, wit mesusy on quicks l e n it s equally Well known that platinum will, net,for-m; an ama gam- It has, therefo e, been pos e tov recover gold a uesm s w ich p rmit the go d to come inte direct contact with mercury, butthis hasv failed to, save the platinum values which are often of g eatervalue an the. gold,

When sodium is added to quicksilver, it intensifies the action thereofand greatly in? creases. its afiin ty' or g d he o um amalgam also hasan affinity f r plat um so that if the latter comes into; contact withit, it will be. amalg m t d T i is be ed to be due to the fact thatthere, is, an afinity between the sodium and the platinum, which causes.the sodium to form c at g o t e. platinum part cles nd, s ce he e is ast ong afiinity betwee the mercu y and e o um, the sodium coatedparticles of platinum will combine with. the ercury- It is. e t that ifa sodium amalgam containing platinum is subjected to some treatment thatwill remove the sodium the platinum Will separate from the. mercury,This is taken advantage oi and the sodium platinum amalgam is subjectedtothe action of; Water which combines with the sodium, forming sodiumhydroxide and hydrogen (Na +H2Q NaOI-I H).

It is. an Object of this invention to produce a machine for the recoveryof gold and platinum Values Which shall be so constructed that it willcontinuously renew the sodium in the mercury so as to provide acontinuous supplyof sodium amalg m hi h is th delivered to the amalg m ig e c o eparato This production of sodium and nascent sodium amal am isproduced by electrolytic means in t 1e manner to be presently described.

My invention can be most clearly described and Will be most readilyunderstood when reference is had to the ac mp ying drawings nuhich thePref r d whe iment st an a e a e p acti ng th i ve iqnhes b eni u tr teda d in which F gure 1 isa tepplan view of e ombined unelg me e andsodium m ga genena :or- Figure 2 s. s ction ta en on: ine, 2:21 H we 1-,a

figure is a s ctiqii. aken Q11. line :3,- Eig'ur F gure is a di metricese tion 0f the me cury ank de ignated 5 i th dra ing as t ken: on l ne Fgu e 2- Figu e 5 s a s ction tak n 11 in Fi ur Figure 6- is. a w ringdiagram; d F gure 7 is a long tud nal, sec ien hreugh one of thelectroly ic cells and i taken on line 7-7, Figure In th aw ngs he sippert ng ram erk ha be e ig at d. as. who y the nusmeral 1 s thereappea s to be. no ne essity ord ntifyi g al e h parts t ere Sun: por edby t is fram erk is s rec pt qr hopper 2wh ch o ains th P lp cb t eated; a. ute 3 extends r m one si e 0f he on-per 2. and, its bottom may beform dy an exten io of th bo om th hopper, The. wa l s of t e h pper-hat l redse pa ed r m. h b t om s as t p ev de w slot 5 through which thepulp may flow. An adj tabl g 6 er es. b: de er ne he rate at which he pup flow rom he o er en oi 'the ch te i Located di ectly b lcw heend fchut .3 is a recovery table preferably consisting of a copper pla 7 hoseupp r s has e amalgamated if des e The pier end f he plate 7 is. bentupward y i t e manner indic t by nume al 8 sQ s to pre ent leak age a dts s d s are secu ed to. the side p e e 9- e d Q-r T e lew dge. o he Pte 7 res s en the p f he upp all c the t ough 1.1 nd iscurved do wa dlyin the manner indicate a 2- A e ts ba 13' s: t nds bet en he side 9 nd10 dire tly ver the center line of the l'fl igll 11 and serves to forcethe pulp to pass down under and against the sodium amalgam hose upper sut cs i i d a ed by in 1% n F gu e After passing underneath the bafflebar 13,

thepulp flows over the edge or apron ofv the trough 11'and ontothe-plate 7A which 17 which serves as a reservoir for a solution ofsodium chloride. This tankhas a faucet 18 which is located directlyabove the electrolytic cell 19. This cell has as carbonanode 20 whichextends longitudinally thereof and is connected with the positive poleof a direct current source 21 (Figure 6) by means of a wire 22. The cellcontains a quantity of mercury 23 which is connected to the negativepole of the current supply by means of the conductor 24. A launder 25 issecured at its upper end to the lower wall ofthe cell 19 and serves tocarry the brine from cell 19 to a similar cell 19A that is located at alower level. It is the intention to have the same number of electrolyticcells as there are plates 7 although itis possible to have a single cellfor serving a plurality of plates. The lower'cell has been designated by19A and the other elements are indicated by the same reference numeralsas the corresponding elements in the upper cell but to which the letterA has been added. .From the lower cell 19A a launder 26 extends to thereservoir 27. A pump 28 which is operated from power derived fromthemotor 29 has its intake port connected with the reservoir 27 by means ofa pipe 30 and its outlet port connected with the tank 17 by means of apipe 31. A branch pipe- 32 extends from the pipe 31 tothe reservoir 27and is controlled by the valve 33. The object of the bypass 32 is topermit the deliveryto tank 17 to be regulated sothat the level of thebrine will remain substantially constant. v I v v A tank 34 is supportedon the framework 1 at a point above the level of the mercury in theuppermost cell 19 and serves as a res ervoir or supply for the mercury.A pipe 35 communicating with the tank 34 has a branch 37 which extendsto the cell 19 and is controlled by a valve 36. A pipe 37Aleading to thecell 19A branches from the pipe 35 and is controlled by a valve 38.'VVhen the machine is in operation, mercury will flow from the tank 34tothe cells 19 and 19A and the rate of flow will be regulated by valves36 and 38.

Referring now to Figure 7, it Will be seen that the cell 19A is providedwith an opening 39A at one end and near the bottom. A pipe 40A. isconnected with this opening and: hasanupward bend 41A which determinesthe level of the mercury which must be a short distance below the loweredge of the anode 20A. Pipe 40A extends over onto the plate-"TA where itterminates in a perforated section 42A. This section of'pipe has itsouter end plugged and is provided with a plurality ofsmall holes43Awhich are located on top and through which the mercury escapes onto theplate 7A, thepipe being lo cated beneath the apron 15 and in closeproximity to the surface of the plate so as substantiallytoavoidfiouring of the mercury delivered therefrom, thereby preventingmaterial loss in mercury and values with the tailings. From the cell 19a'similar pipe 40 extends. The corresponding parts of this pipe have thesame reference numerals as those given above, but with the letter Aomitted.

Referring now more particularly to Figure 5', it will be observed thatthe bottom or trough 11 is inclined from the ends of the middle point,which has been indicated'by numeral 44. A hole extends through thebottom at point 44 and to this a valve 45 is connected.

A pipe 46 extends fromthis valve to the clean out 47 to whose lower endor-bottom a stop cock 48 is secured. A pipe 49 has its lower endconnected with the clean-out 47 and its upper end bent into a gooseneck50 whose height determines the level 14015 the mercury.

The end of the gooseneck terminates over the inclined trough 51. o

The lower end of the trough 51 has an open ing 52 from which a pipe 53extends downwardly and terminates a short distance be- 'low the upperend of the tank 54. A conical canvas strainer55 is securedto the upper,end of thetank 54 in the manner shown in Figure 4. A drain cock 56 isconnected to the bottom of the tank 54 andis employed when the tank isto be drained.

From the tank 54 a pipe 57 extends to the pan 58 which can be subjectedto a spray of water from the pipe- 59. From the pan 58 a pipe 60 extendsto the mercury pump 61,

which is driven from the motor 62. This pump discharges the mercurythrough pipes 63 and 64 into tank 34 from which it flows into the cells19 and 19A.

Let us now assume that the parts are assembled in the manner shown anddescribed and that the hopper 12 is filled with pulp, meaning pulverizedore mixed with water containing metallic gold and platinum; that tankl'?is filled with a sodium chloride brine and that tank 34 containsmercury. The generator 21 is connected with the anodes 20 and themercury cathodes 23. The faucet18 is opened and brine is allowedto'flow. 1 This brine fills the cell 19 and overflows onto the launder25 [mm which it enters the cell 19A and from suitable means (not shown).The sodium readily combines with the mercury and forms a sodium amalgam.The intensity of the electric current and the rate of flow of the mer--cnry is adjusted so that when the mercury leaves the cells it willcontain about three onehundredths of one per cent of sodium. The sodiumamalgam now passes through th pipes 40 and 40A and elnergingthrough theholes 43, 43A, falls upon the respective plates 7, 7A, establishing uponeach of the latter a bed or coating which gradually moves down over thesurface of its plate. The sodium amalgam passing over the plate 7delivers into the trough 11, while the amalgam flowing over the plate 7Adelivers into the trough 11A. The wet pulp flowing from the chute orlaunder 3 impinges directly on the bed. of alkali metal amalgam flowingover the plate 7 at a region where the amalgam is substantially free ofoverlying matter, thus promoting penetration of the surface film of theflowing amalgam bed and better envelopment and amalgamating contact ofthe solid particles of the pulp with the amalgam. Similarly the pulpwhich overflows from the trough 11 and passes over the edge or apron 15of the latter falls directly on the bed or" amalgam on the plate 7A at aregion where the amalgam is relatively tree of overlying matter. Whenthe pulp delivered from the launder 3 or overflowing from the trough 11impinges upon the sodium amalgam flowing over the plate or the plate 7A,as the case may be, the water 01" the pulp combines with the sodium andforms sodium hydroxide which is a powerful cleansing medium that removesany oily film from the gold and platinum, whereby the metal itselfbecomes e3:- posed so that itwill have good contact with and be actedupon by the amalgam. The chemical change which occurs when the water ofthe pulp reacts upon the sodium amalgam also has the effect of greatlydecreasing the surface tension of the flowing bed of amaigam and therebycontributes to the more effecmve envelopment and amalgamating contact ofthe metallic particles of the pulp. In its course through the apparatusthe pulp flows from the hopper 2 through the chute 3 and is deliveredupon the bed of amalgam flowing over the plate 7. At the lower end ofthis plate the pulp enters the trough 11 and passes underneath thebaflleblock 13 therein, thence delivering over the edge or apron 15 ofthe trough 11 and falling upon the'surface of the amalgam bed which isflowing down over the plate 7A. At the lower end of this latter platethe pulp delivers intothe trough 11A and after passing beneath thebattle block 13A therein flows into the chute 16. Upon passing beneaththe bafiie plates 13, 13A, the pulp is forced against the surface of theamalgam so that the lattercomes in contact with the gold platinum. Thegreater part of the values are recovered on the uppermost plate and byusing several plates in series a thorough recovery can he obtained.

As the amalgam flows from the troughs 11 and 11A, it passes through therespective pipes 46 into the corresponding clean-out traps 4L7 where thevalues of gold and platinum settie to the bottom due to their greatdensity. The mercury passes from the traps through pipes 49 respectivelyleading there- 33011! and flows into the trough 51 and down into thecanvas. strainer 55 where any large particles are separated. Themercurythat passes through the canvas strainer enters the tank. 5% wherefurther separation takes place and from which the settlings may beremoved through the cock 56. The lighter mercury or sodium amaigam flowsthrough pipe 57 to the pan 58 where the action of the water sprayremoves any trace of sodium that may stillbe present and sincemercuryalone has no aiiinity for platinum, any platinum which may bepresent, when. the amalgam enters pan 58 will immediately be releasedand will settle to the bottom. If any gold or platinum still remainsafter the mercury returns to tank 34, it will stay in the mercury streamuntil it settles to the bottom in some one of the several clean-outtraps.

-' I want to call particular attention to the fact that there is acontinuous supply of nascent sodium amalgam which is supplied to theseparator, and which, when subjected to the action of the water in thepulp, results in the production of sodium hydroxide which dissolves anygrease or fat that may be on the metal particles.

The sodium amalgam, above explained, is more active than mercury andhasthe prop erty of combining with platinum so that these values will herecovered. This, therefore, makes this apparatus and method veryvaluable in platinum mining as it has heretofore been very diiiicult torecover the platinum.

Having now described the invention what is claimed as new is:

1. In combination, a plurality of amalgamating plates in tandem, meansfor flowing pulp containing values over said plates in succession, ameans for preparing alkali metal amalgam and means for conveying meansindependently to the head of each of said plates and'distributing itthereover.

2. In combination,; a plurality of amal gamating plates in tandem, meansfor flow ing pulp containing values over alkali metal amalgam, means forconveying said 'amalgam'di-rectly' from said preparing preparing meansindependently to the hcad f means independentlyto the head of each ofsaid plates and-"distributing it thereover, and

a trapbetween'each two plates for catching i an d (allow- I a flowingbed of alkal1 metal amalgamupon the mercuryand'metal amalgam ing thepulp stream to pass on.

3; In combination a plurality of inclined amalgamating plates in tandem,means for flowing pulpover-said plates in succession, a conduit forsodium amalgam transversely arranged at the head of each plate and opento allow the amalgam to 'pass' to the plate, means for protecting saidconduit from the pulp stream as it is fed to the plate, means saidplates-insuccession, agmeans for preparingand flow asa thin sheet withthe amalgam bed and thereafter causing the pulp to come into contact,with additional vcontinuously flowing alkali'metal amalgam.

a flowing bed ofalkali metal amalgam upon a surface, and causing wetpulp containing:

The process that consists inestablishing values to impinge upon theupper surface of theainalgam bedat a region where the latter issubstantially free of overlying matter and to flow with said bed. v 10,The process that comprises establishing a surface and causing wet pulpcontaining upper surface of andto flow freelywith the amal am bed andcontinuously renewing the strengthof the flowing amalgam.

JAMES E HOPKINS, I

for preparingsodium amalgam and means for conveying said amalgamdirectly from said preparing means andindependently to said conduit ofeach plate. 4. In combination, a plurality of incline amalgamatingplatespositioned to cooperate so that the material to be tr'eatedymay passfrom the tail of one to-thehead ofanother,

means foriflowing pulp containing values over said plates in succession,a means for preparing alkali metal amalgam, and a means for conveying sad amalgam directly fromsald of each-of said thereover. i p I 5. Incombination, a plurality ofamalgamating plate sections positionedtocooperate so that the material to betreated may pass from one to theother, means for flowing pulp plates and distributing it containingvalues over said plate sections in succession, means for preparingalkali metal amalgam, and means for, conveying said amalgam directlyfrom said preparing means independently toeach of'said plate sectionsand distributing it thereover.

6; The process of flowing wet pulp over an extended mercury surface andfeeding fresh- 1y prepared sodium amalgam independently to the surfacein proximity to the point of'delivering" the pulp to said surface,'andvat a plurality of spaced. intervals along the path of flow'to-maintain the mercury surface at maximum efficiency, 7. The'prccessthatconslsts in aflowing bed of alkali metal amalgam upon a 1 surface andcauslng wet pulp containing,

establishing

